The present invention broadly relates to motion detectors and is particularly directed to motion detection systems adapted for use in detecting directional movement of an object through a threshold and for generating a selected audio or video output in response thereto.
The use of motion detectors is widely known in the prior art. Indeed, motion detectors have been employed in a variety of applications in the past for the purpose of monitoring movement of an object within a confined region. One of the predominate applications for motion detectors is to detect the presence of an individual. For example, the entrances to many retail stores are provided with motion detectors which either audibly or visually indicate to store personnel when customers enter and leave the store. Retail stores also employ similar systems as a security measure, for example, to alert store personnel of a potential theft when a customer leaves the store with an item which has not been purchased.
The concept of motion detection is, in fact, widely employed in many security systems. For example, motion detectors are predominant in home security systems to detect the presence of burglars. Such devices are regularly found both inside the home and outside the home and, once activated, are operative to trigger an alarm or other appropriate signal to indicate the presence of an unauthorized individual. Various types of personal items, such as brief cases, automobiles and the like, are particularly subject to theft and many prior proposals are directed to the requirements for protecting such items.
Despite the proliferation of motion detectors for use in a variety of different applications, it has not heretofore been known to employ motion detectors specifically for the purpose of detecting directional movement of an object through a threshold. Such a motion detection system which discriminates between directional movement could be used in a variety of different applications to provide output data indicative of the directional movement. For example, a directional sensing device could be utilized in retail stores to provide valuable information to business owners. To illustrate, business owners could use information reflecting the accumulated number of customers entering the store, or passing by a particular display within the store, to devise improved marketing strategies. Such information, when compared to the number of sales generated over the same period of time, might also be indicative of the success of various types of advertising schemes as well as the work performance of store personnel. On an individual level, a homeowner could use such a directional sensing device, for example, to trigger a selected event, such as the opening or closing of a garage door upon movement of a vehicle across the threshold.
Regardless of its particular application, it would desirable to improve upon existing motion detection technology by providing a motion detection system which discerns directional movement of an object and generates a selected output in response thereto. The present invention is directed to meeting these needs.
It is an object of the present invention to provide a new and improved motion detection system adapted for use in detecting movement of an object in selected movement direction through a threshold.
Another object of the present invention is provide such a motion detection system which indicates directional movement of the object through the threshold either audibly, visually or both;
A further object of the present invention is to provide a motion detection system which visually indicates accumulated occurrences of motion through the threshold in a selected movement direction;
Yet another object of the present invention is to provide a new and improved motion detection system which may be situated proximately to an entryway to detect directional movement of an object, while providing desired output at a remote location in response to such movement;
Still a further object of the present invention is to provide a motion detection system which is relative easy to construct and inexpensive to manufacture;
It is still a further object of the present invention to provide a new and improved method of detecting directional movement of an object through a threshold.
In accordance with these objectives, a motion detection system is provided and adapted for use in detecting directional movement of an object through a threshold. According to an exemplary embodiment of the present invention, the motion detection system broadly comprises first and second transmitters each operative to produce first and second broadcast signals, respectively, along first and second transmission paths that cross the threshold. A receiver circuitry operates in an absence of movement of the object through the threshold to receive the first and second broadcast signals and to generate a receiver circuitry reference signal. The receiver circuitry is further operative upon interruption by the object of both the first and second broadcast signals within a selected period time to generate a receiver circuitry interrupted output, corresponding to movement of the object, respectively, through the first and second transmission paths. Processing circuitry monitors the receiver circuitry and operates in response to detection of the receiver circuitry interrupted output corresponding to movement of the object in either a first or second movement direction, to produce an event detection signal. Output circuitry receives the event detection signal and generates a selected output in response thereto, thereby to indicate directional movement of the object in at least one of the first and second movement directions.
In another embodiment of the present invention, the processing circuitry produces a plurality of event detection signals, and a plurality of output circuits are provided for receiving a respective one of the event detection signals and generating selected output in response thereto. Here, a switching circuitry is provided which includes a plurality of switch elements each having a first switch mode wherein a respective one of the output circuits is activated and a second switch mode wherein a respective one of the output circuits is inactivated.
Preferably, the first and second broadcast signals are each pulsating signals having a selected broadcast signal frequency and amplitude. Each of the first and second broadcast signal frequencies is preferably in the infra-red range. To this end, the first and second transmitters may be infra-red light emitted diodes. It is also preferred that the first and second broadcast signals be 180xc2x0 out of phase with respect to one another with the output of the receiver circuitry being a composite of the first and second broadcast signals.
The output circuitry may be in the form of a visual display which visually indicates each occurrence of movement through the threshold in at least one of the first and second movement directions. It is preferred that the event detection signal generated by the processing circuitry contain serial data so that the visual display can numerically indicate accumulated occurrences through the threshold in a desired movement direction. A reset circuit may be associated with the visual display to clear the display, as desired.
Alternatively, the output circuitry may be in the form of an audio circuit which audibly indicates each occurrence of movement through the threshold in at least one of the first and second movement directions. Here, the audio circuit may transmit a selected pre-recorded message upon each occurrence of movement through the threshold. Preferably, the audio circuit includes a programmable integrated circuit device and a speaker element providing this annunciation capability. Preferably also, the audio circuit includes an external microphone element and a record switch adapted for use therewith, such that the integrated circuit device is operative upon actuation of the record switch to store voice messages received by the microphone element into memory.
In order to discriminate directional movement, a direction indicator switch may be provided, with this indicator switch operative in first mode to cause the processing circuitry to produce the event detection signal only upon movement of the object through the threshold in the first movement direction, and operative in a second switch mode to cause the processing circuitry to produce the event detection signal only upon movement in the second movement direction.
Where the motion detection system of the present invention is employed in an entryway, the first and second transmitters and the receiver circuitry may be contained within a common housing positioned on one side of the threshold, with the receiver circuitry including a receiver preferably interposed between the first and second transmitters. With such a construction, a reflector element is provided on an opposite side of the threshold such that the first and second broadcast signals are reflected toward the receiver circuitry. The present invention, though, also contemplates an alternative arrangement wherein the transmitters are located across the threshold from the receiver circuitry. Regardless of the particular configuration, the selected output circuitry may be either contained within the housing or located remotely thereof.
The present invention also contemplates a methodology for detecting movement of an object through a threshold in a selected movement direction. Here, the methodology broadly comprises the steps of: (1) transmitting first and second broadcast signals across the threshold along respective first and second transmission paths; (2) generating an event detection signal upon sequential interruption of the first and second broadcast signals within a selected period of time; and (3) generating a selected output in response to the event detection signal.